Efficient removal of pollutants from olive washing wastewater in bubble-column bioreactor by Trametes versicolor

The white-rot fungi Panus tigrinus, Funalia trogii and Trametes versicolor have been tested in shake flasks for the reduction of olive washing wastewater (OWW) pollutants and production of oxidases on OWW-based media. P. tigrinus was rejected for its scarce performance. F. trogii showed best production of laccase (27 000 U g⁻¹), while T. versicolor appeared a good pollutant degrader reducing colour, COD and phenols by 60, 72 and 87%, respectively. Only T. versicolor grew well in bubble-column bioreactor: its OWW depollution, in continuous process, led to colour, COD and phenols reduction by 65%, 73% and 89%, respectively. Optimal dilution rate was 0.225 d⁻¹ (0.225 m³ of effluent treated daily per m³ of bioreactor). Thus, a small bioreactor (10 m³) could treat daily the amount of OWW produced by a standard olive washing machine (2 m³ d⁻¹). For these reasons, this process could be proposed as a simple, efficient and low-cost OWW treatment.     

Influence of papermill sludge on growth of Medicago sativa, Festuca rubra and Agropyron trachycaulum in gold mine tailings: a greenhouse study

A greenhouse study was undertaken to determine the suitability of adding papermill sludge to neutral/alkaline gold mine tailings to improve the establishment of Festuca rubra, Agropyron trachycaulum and Medicago sativa. Festuca rubra root and shoot biomass and A. Trachycaulum shoot biomass were increased with papermill sludge amendment. The addition of papermill sludge and fertilizer drastically increased the shoot and root biomass of M. sativa (20-30 times) while A. trachycaulum and F. rubra showed a more moderate increase in growth. Photosynthetic pigment content of the leaves was higher in papermill sludge treatments than in the treatments without papermill sludge. The organic carbon content, macro-aggregate content and field capacity of the gold mine tailings were increased while the bulk density was decreased by the addition of papermill sludge. This study suggests that addition of papermill sludge and adequate fertilization can alleviate some of the adverse conditions of neutral/alkaline gold mine tailings.     

Comparison of benthic macroinvertebrate indices for the assessment of the impact of acid mine drainage on an Irish river below an abandoned Cu-S mine

A range of macroinvertebrate indices were compared to assess the most appropriate metric for the assessment of acid mine drainage (AMD) in a low alkalinity, highly erosional river in south-east Ireland. Differences were found in the ability of indices to discriminate AMD impact with the Brillouin, BMWP score, Margalef and Shannon Indices the most precise. Taxon richness was also strongly correlated with AMD indicator parameters (e.g. pH alkalinity, sulphate, Zn and Fe) at impacted sites being an equally reliable metric. The response of the community structure to AMD in this river does not fulfil the optimum criteria for either diversity or biological indices, which may explain the variation in the success of different indices seen in this and other studies. The development of indices that model the expected community response to AMD more accurately or are based on the response of indicator species to AMD pollutants are required.     

二氧化氯-接触催化氧化联合去除水中铁和锰

为了解决水体中铁锰季节性超标的问题,提出一种既能够减少化学试剂的使用又能有效去除铁锰的经济有效的方法。研究了单一方法(二氧化氯氧化法、接触催化氧化法)及两者联合对铁锰的去除效果,提出用二氧化氯氧化-锰砂过滤联合方法解决。研究表明,用ClO2氧化去除水中Fe2+的反应先发生、速率较快且效果较好,而与Mn2+反应则较慢并且不能完全转化为沉淀。单纯接触催化氧化法需要较长时间,过滤层才能达到稳定且较好的处理效果,培养过程中其除锰效果并不理想。两者联合时,利用过滤层的吸附作用去除部分铁锰,减少了氧化剂的使用。初期3个柱的除Mn2+效果都比较好,去除率均大于80%;然而采用石英砂或纤维束滤料的滤柱去除Mn2+的效果随时间变差,但采用锰砂的除锰效果在实验期间始终维持在较高水平。     

基于玄武岩纤维载体的生物膜法净化污染河道水体

为考察不同水体环境状况下,所构建的基于玄武岩纤维的污染河道水体净化技术的净化效能,通过模拟不同p H、温度及DO的污染河道水体环境,研究了水体中的COD、氨氮及TP指标变化规律,得到所构建的净化技术对COD、氨氮及TP的削减速率。研究结果表明,不同温度环境下COD、氨氮及TP的净化效率会随着时间增加而增强;不同DO环境下COD、氨氮及TP的净化效率随时间增加而增强;不同p H条件下COD净化效率随着时间增加而持续增强,氨氮净化效率随时间增加至某一极值后趋于平稳,而TP的净化效率会随着时间增加表现先升高后降低的趋势。此外,实验期间不同水体环境下COD、氨氮与TP皆在温度20~25℃,p H为7,DO为2~4 mg/L时分别获得93%、90%和36%的最大净化效率;根据实验结果得出的最适宜水体环境为温度20~25℃,p H为7,DO为2~4 mg/L;COD、氨氮及TP削减速率分别为0.63~0.84、3.6×10-3~4.0×10-2和7.1×10-4~2.9×10-3kg/(m3·d)。     

Comparison of different pre-treatment methods for enriching hydrogen-producing bacteria from intertidal sludge

Batch tests of cultivations were conducted to analyze influences of pre-treatment methods (heat–shock, acid, and alkaline) on hydrogen production. The hydrogen yields of the pre-treated samples were significantly higher than those without pre-treatment. Heat–shock pre-treatment yielded maximum hydrogen (75.5 ± 4.0 mL/g sucrose_removed), and had the highest sucrose removal efficiency (81.20 ± 1.23%). Heat–shock pre-treatment produced more ethanol and acetate (80.44 ± 0.55% of the total soluble metabolites), which belonged to ethanol-type fermentation. Denaturing gradient gel electrophoresis (DGGE) profiles showed that pre-treatment methods affected the composition of microbial communities. The results showed that pre-treatment methods play a key role in the hydrogen production process of marine hydrogen-producing microflora.     

Biological activity and bioavailability of grain bound 14C‐malathion residues in rats

Abstract

Paddy (unmilled rice), milled rice and maize‐bound ¹⁴C residues were prepared using ¹⁴C‐succinate‐labelled malathion at 10 and 152 ppm. After 3 months, the bound residues accounted for 12%, 6.5% and 17.7% of the applied dose in paddy, milled rice and maize respectively in the grains treated at 10 ppm. The corresponding values for the 152 ppm were 16.6%, 8.5% and 18.8%. Rats fed milled rice ‐ bound ¹⁴C‐residues eliminated 61% of the ¹⁴C in the faeces and 28% in the urine. The corresponding percentages for paddy and maize were 72%, 9% and 53%, 41% respectively; indicating that bound residues from milled rice and maize were moderately bioavailable. When rice‐bound malathion residues (0.65 ppm in feed) were administered to rats in a 5 week feeding study, no signs of toxicity were observed. Plasma and RBC cholinesterase activities were slightly inhibited: blood urea nitrogen was significantly elevated in the test animals. Other parameters examined showed no or marginal changes.     

Biological monitoring of chlorpyrifos exposure to rice farmers in Vietnam

Chlorpyrifos is the most common organophosphate insecticide registered for use in Vietnam and is widely used in agriculture, particularly rice farming. However, chlorpyrifos exposure to and adverse effects on farmers has not been evaluated. In this study, biological monitoring of chlorpyrifos exposure in a group of rice farmers was conducted after a typical application event using back-pack spraying.Urine samples (24 h) were collected from the rice farmers before and post insecticide application. Samples were analysed for 3,5,6-trichloropyridinol (TCP), the major urinary metabolite of chlorpyrifos, using an enzymatic pre-treatment before extraction followed by HPLC-MS/MS. Absorbed Daily Dose (ADD) of chlorpyrifos for farmers were then estimated from urinary TCP levels, expressed as μg g⁻¹ creatinine. The analytical method for urinary TCP had a low detection limit (0.6 μg L⁻¹), acceptable recovery values (80-114%), and low relative percentage differences in duplicate and repeated samples.Post-application chlorpyrifos ADD of farmers varied from 0.4 to 94.2 μg kg⁻¹ (body weight) d⁻¹ with a mean of 19.4 μg kg⁻¹ d⁻¹ which was approximately 80-fold higher than the mean baseline exposure level (0.24 μg kg⁻¹ d⁻¹). Hazard Quotients (ratio of the mean ADD for rice farmers to acute oral reference dose) calculated using acute oral reference doses recommended by United States and Australian agencies varied from 2.1 (Australian NRA), 4.2 (US EPA) to 6.9 (ATSDR).Biological monitoring using HPLC-MS/MS analysis of urinary TCP (24 h) was found to be an effective method for measuring chlorpyrifos exposure among farmers. This case study found that Vietnamese rice farmers had relatively high exposures to chlorpyrifos after application, which were likely to have adverse health effects.     

PM(10)-bound polycyclic aromatic hydrocarbons: biological indicators, lung cancer risk of realistic receptors and 'source-exposure-effect relationship' under different source scenarios

Cancer has become a critical health issue in the world heritage city Kandy, Sri Lanka. Polycyclic aromatic hydrocarbons (PAHs), one of persistent organic pollutants, in the atmosphere may be a major etiological factor in lung carcinogenicity. Over the very high concentrations of ambient air PAHs reported in Kandy, this paper is focused on setting priorities to control human exposure to PAHs in prevention of cancer.On re-appraisal of the classical indicator benzo(a)pyrene (B[a]P) for atmospheric PAHs-related carcinogenicity, B[a]P failed to reflect the toxicity completely and may not be the sole indicator for risk assessment studies in complex multi-sourced urban environments. The excess lifetime lung cancer risks of atmospheric PAHs with ‘less than lifetime exposure’ were assessed based on both ‘B[a]P toxic equivalents’ and ‘B[a]P surrogate epidemiological’ approach of risk quantification, over emissions characterized urban, suburban, and rural areas of Kandy. In urban heavy traffic areas, PAH-related additional cancer burden has been 942 million⁻¹ over 30 y of exposure. Over the whole study area, ∑p-PAHs show strong correlation (r = 0.8) to the predicted risk levels. While the urban and suburban predicted cancer risk levels could not show significant correlation to their emission sources indicating the real complexity in mega urban environments, the rural lung cancer risk levels correlated perfectly with the source, firewood combustion.Policy decisions on environment and health could be based on established correlations among ‘emission sources-exposures-health effects’. The priority for “analysis of options and policy formulation to reduce inhalation PAHs exposure of population in Kandy” was considered “moderate to high”.     

利用生物曝气滤池修复受污染水源

利用生物曝气滤池(BAF)对微污染水源水去除氨氮及有机物进行了试验研究。试验表明,在进水氨氮为6mg／L左右时,BAF可在8m／h的滤速下运行,氨氮去除率大于88％;在氨氮进水为2mg／L时,BAF可在16m／h的滤速下运行,氨氮去除率大于84％。BAF对水中的三氯甲烷前体物去除率较低(16％),对AOC的去除率为58％。BAF中载体上的生物膜主要聚集在表面的凹陷和孔洞处,不能完全覆盖载体表面。